Foreign materials such as iron powder, fibers, weld sealers, and press forming oil, which adhere to a body of a vehicle during various processes at a press shop or a welding shop, hinder a paint process. Accordingly, the automotive body is immersed in a processing liquid during a degreasing process that is an initial process at a paint shop in order to remove adherent foreign material.
Conventionally, the removal of foreign material involves moving an automotive body immersed in a processing liquid against a counterflow of the processing liquid and removing foreign material using ultrasound and high-pressure jets of a cleaning liquid. In a known procedure, foreign material removed from the automotive body is then extracted together with the cleaning liquid from an extraction outlet provided on a bottom part of a cleaning tank, and the foreign material is separated from the cleaning liquid by a cleaning liquid reprocessing device in order to reuse the cleaning liquid (for example, refer to Patent Document 1).
In addition, a configuration is disclosed in which foreign material settled on a bottom part of a recovery tank in a pre-paint processing device is separated by a liquid cyclone into a processing liquid in which the foreign material is diluted and a processing liquid in which the foreign material is concentrated, the processing liquid containing the diluted foreign material is returned to the recovery tank to be reused as processing liquid, and the processing liquid containing the concentrated foreign material is once more separated into processing liquid and foreign material by a conveyor-type filter (for example, refer to Patent Document 2).
Patent Document 1: Japanese Patent Laid-Open No. 2004-162157
Patent Document 2: Japanese Patent Laid-Open No. 11-047666